How exactly did you go about calculating who has the bigger audience?
Its not easy, you have to read 1000s of history books to make a fair judgement, which I have done.
You also must distiguish fame in their own time from fame after death.
Most people have an easier time determining who is still famous now than in their own time. But being famous in your own time is more critical in my opinion because once you achieve fame, you have a large audience. Typically, the most creative thinkers in history are those gain a large audience.
Of those on the list who were the most famous in their time, I'd say that Origen of Alexandria (185-254) is number one, the most famous. He was the first famous Christain in history who was known all over the Roman Empire. He was so well regarded that the wife of the Roman Emperor sought him out for personal teaching. This was in time time when Christianity was persecuted.
Origen wrote more books than any other single author in history, about 6000 of them (according to Epiphanius, his enemy), many which still remain. He employed many scribes. He memorized the entire Bible, and wrote multiple books at the same time, much like a chess grandmaster playing games against multiple opponents at once, moving around a circle making one move at a time.
Origen had 8 scribes in a circle. He wrote 8 books at one time, dictating a sentence or paragraph for each scribe for each book as he moved around the circle. He kept this pace up for decades, until the Romans nabbed him and had him tortured.
Origen also was fluent in several languages including Greek, Latin, Hebrew, Syriac, and others. He took different manuscripts of the Bible, and arranged them in parallel columns, 6 to 8, comparing the text by different scribes and in different languages, a gargantuan effort.
In those times, there were not many books. As you can imagine, Origen's books were distributed all over the Roman Empire, flooding the market.
Origen became known as Adamantius, the Man of Steel, and was very popular up until about 400 A.D. when the anti-Liberty, pro-Augustine pro-state forces started to attack Origen in death (even thought they borrowed a large chunk of their stuff from him). Augustine couldn't even read Greek! Then around 550, more anti-Origen forces launched another onslaught against Origen (who had now been dead 300 years).
Frankly, there was a war for liberty raging for 150 years, from the attacks of 400 by Methodius and Augustine, until the Council of Chalcedon in 451, when Justinian clamped down on Origen. Origen's defenders fought vainly for liberty during these times, but then the dark age began.
You won't find any support for the crusades in Origen, but you will in Augustine.
Origen was a man who defended human liberty like no other has done before or since.
He promoted the human soul to be free and to think, and to resist government authority. He promoted doctrines that lead to a free society, like mercy. Origen believed that the devil could be saved!
Origen also synthesized Greek philosophy with the Bible, so the ideas of Greek liberty could be learned by Christians.
To get an idea of what he was like, please check out:
Early Opposition to Origen
http://hellbusters.8m.com/upd10.html
Origen--Continued
http://hellbusters.8m.com/upd11.html
The Eulogists of Origen
http://hellbusters.8m.com/upd12.html
Augustine and Origen Contrasted
http://hellbusters.8m.com/upd20.html
This is what I mean by fame. Origen was the foremost intellectual in the world, from his time in the early 200s, well into the 500s. He changed world history forever. There has never been a man who ever lived who did what Origen did. We today, are all the better for it.
Even today, the part of Christianity that is good and promotes liberty can be traced back to Origen.
Rothbard is nothing but a pimple on an elephant's ass when come comes to comparing Origen with Rothbard's impact on the history of liberty
PS
Usually, the more famous people get, the less radical they get. Not so with Origen.
Origen said:
"It is not irrational, then, to form associations in opposition to existing laws, if done for the sake of the truth. For as those persons would do well who should enter into a secret association in order to put to death a tyrant who had seized upon the liberties of a state, so Christians also, when tyrannized over by him who is called the devil, and by falsehood, form leagues contrary to the laws of the devil, against his power, and for the safety of those others whom they may succeed in persuading to revolt from a government which is, as it were, "Scythian," and despotic."
Contra Celsus (248 a.d.) 
